This invention relates to an intravenous cardiac pacemaker electrode having a securing element which serves to secure the electrode in the heart and which is mounted on a plunger that is displaceable within a hollow cylindrical. The securing element may be drawn back into the hollow cylinder to assume a protected position for introducing the electrode into the patient.
A pacemaker electrode of the above-outlined type is disclosed, for example, in German Laid-Open Application (Offenlegungsschrift) No. 2,133,304.
An electrode of the above-outlined type has the disadvantage that during its introduction under X-ray monitoring, the implanting surgeons cannot determine from the X-ray image with sufficient clarity whether the securing element is in an extended or in a withdrawn position.
For the purpose of ensuring a complication-free intervention, it is desirable that the implanting surgeon be capable to determine at all times without additional auxiliary means or actions the position of the securing element. This is of particular significance when the electrode has to be removed from an original secured position and has to be displaced to another region of the heart.
A possibility of X-ray monitoring of the implantation of pacemaker electrodes is mentioned in U.S. Pat. No. 3,754,555 in column 2, lines 28-30. It is a disadvantage of the electrode disclosed in this patent as well that the securing element for attaching the electrode in the heart chamber has to be made of a metal which has a predetermined minimum thickness to ensure that it is clearly visible in an X-ray image.